Pyrido [2, 3-d] pyrimidine-2, 4, 5, 7-tetraones



United States Patent 3,139,432 PYRIDO{2,3-d]PYRIMfIDlNE-2,4,5,7- nTRAONES Homer C. Scarborough, Evansville, Ind, assignor to Mead Johnson 8: Company, Evansville, Ind a corporation of Indiana No Drawing. Filed June 24, 1.963, Ser. No. 290,205 13 Claims. (Cl. 260-4564) The present invention is concerned with heterocyclic compounds of Formula I and with the alkali metal salts thereof.

1 FORMULA I o 0 on o H u n n N-RB R3 l L e l L o: -o o o N N N N I l 1 1 I! 1'};

In these formulas and throughout the present patent application, R R and R refer to hydrogen atoms or methyl groups, and R refers to a hydrogen atom or a lower alkyl group having up to about 6 carbon atoms. Formula I represents equivalent tautomeric forms of the same compound, (Ia) being the S-keto form and (lb being the S-enol form. The separate forms under certain conditions may co-exist in tautomeric equilibrium, as shown. As is usual in the art, the keto and enol forms (Ia and 1b) are regarded as equivalents for practical purposes. When one or more of R R and R are hydrogen, other enolic forms involving one or more of the oxygen atoms in the 2, 4, and 7 positions are sometimes formed. Each such tautomer is considered part of the present invention.

The above substances comprise a new class ofchemical compounds known as pyridol[2,3-d]pyrimidine-2,4,5]- 1H,3H,8H]tetraones (Formula la) or S-hydroxypyrido [2,3-d]pyridimidine-2,4,7-[1H,3H,8H]triones (Formula Ib). They bear a functional relationship to the biologically active purines in which the imidazoline ring thereof is replaced by the dioxo pyridine ring of similar acidic character.

The products of the present invention are active pharmacologic agents which have been shown by animal tests to variously possess central nervous system stimulating, bronchodilator, uricosuric, and anti-inflammatory properties when administered in doses ranging from 50 to 400 mg./kg. of body weight.

The compounds of Formula I are prepared by reacting a 4-aminouracil or 4-methylaminouracil, either of which if desired may bear methyl groups in the land/ or 3- positions, with malonic acid or an alkyl mono-substituted malonic acid in the presence of a condensing agent.

The process is illustrated by Equation a.

EQUATION a Suitable condensing agents include the lower alkanoic anhydrides such as acetic anhydride, propionic anhydride, or butyric anhydride. Acetic anhydride is the preferred condensing agent. In some instances an inert organic liquid solvent may be advantageously employed to assist in the formation of a homogeneous reaction medium. Acetic acid is preferred for the latter purpose. The

reaction takes place spontaneously on mixing of the reactants and condensing agent, as is evidenced by the evolution of heat. It is preferred, however, to carry out the process at somewhat elevated temperatures, temperatures in the range-of 30100 C. being preferred. At temperatures substantially in excess of C. reduced yields are sometimes obtained as a result of decomposition of the malonic acid reactant.

The following examples are provided to further illustrate the manner of practicing the present invention. They are not to be considered the sole embodiments thereof, however, and are provided only for illustrative purposes. Corrected melting points are reported.

Example 1 1,3,6,8-tetramethylpyrido[2,3 d] pyrimidine-2,4,5]- [1H,3H,6H,8H]tetraone.-A mixture of 8.45 g. (0.05 mole) of 1,3-dirnethyl-4-(methylamino)uracil, 7.1 g. of methylmalonic acid, 11.3 ml. (0.12 mole) of acetic anhydride and 10 ml. of acetic acid is heated on the'steam bath for 2 hrs. During this time the suspended reactants dissolve and'the solution boils gently. The solution is then cooled in an ice bath with the formation of a precipitate. The crystallized product is collected by filtration. The crystalline material is recrystallized from acetonitrile yielding the purified product in 48% yield based on uracil reactant, M.P. 259.5260.5 C.

Analysis: C, 52.66; H, 5.22; N, 16.90.

Examples 2-7 The procedure of Example 1 is repeated employing the following reactants as described for 1,3-dimethyl-4- (methylamino)uracil and methylmalonic acid in that example.

Example 2:

4-aminouracil Malonic acid Example 3:

1,3-dimethyl-4-arninouracil Malonic acid Example 4:

1,3-dimethyl-4- (methylamino uracil Malonic acid Example 5:

1,3-dirnethyl-4-arninouracil methylmalonic acid Example 6:

1,3-dirnethyl-4-aminouracil n-Butylmalonic acid Example 7:

1,3-dimethyl-4-(methylamino)uracil n-Butylmalonic acid The formulas, analyses, percent yield, and solvents used for recrystallization of the products produced by Examples 2 through 7 are arranged in the following table. Each of the substances described in Examples 1 through 7 is soluble in 5% aqueous sodium hydroxide and is reprecipitated therefrom by neutralization of the solution with acid. These products are insoluble in 10% aqueous sodium carbonate solution.

The products of Examples 1, 3, 4, 5, and 6 were concluded to exist in the 5-enol form (Formula when dissolved in dimethylsulfoxide. Solutions thereof in dimethylsulfoxide having concentrations of 10% (w./v.) exhibited resonance at 745 cycles/ sec. which value was not altered in frequency by dilution of the solution. This is characteristic of an intramolecularly hydrogen-bonded hydroxyl group. The products of Examples 3 and 4 in which R is hydrogen each exhibited resonance at 358 3 4 and 338 cycles/sec. also, which is characteristic of a and the alkali metal salts thereof, wherein R is selected hydrogen atom attached to a carbon-carbon double-bond. from the group consisting of hydrogen and lower alkyl,

The products of Examples 1 and 5 in which R is methyl and R R and R are selected from the group consistexhibited resonance at 115 and 113 cycles/sec. which is i f hydrogen nd methyl,

characteristic of a methyl group attached to a carbon- 5 2 1 3 dimethylpyridopfi d]Py1-imidine 2 4 5 carbon double-bond. [1H,3H6H,$H]tetraone Examples 27 PYRIDO[2,3-d]PYRIMIDINE-2,4,5,7[1H,3II,6H,8H]TETRAONES AND fi-ENOL EQUIVALENTS O O OH O H ll H H l N-R A O I gs 1' 1 Rccrystal- Analysis Example R R R R M.P.( 0.) Yield, Formula lization No. Percent Solvent C H N H H II 82 C1H N3O a 21.64 CH3 H II 280282.5 45 CDI'ION304 ed, c 48.48 4.11 18.91 CH3 H CH 220.5-222.5 46 5 C10H11Na04-- 50.64 4.66 17.68 CH3 CH 287.5289.5 58 C10H11N304-- 50.91 4.76 17.82 CH3 CH3 CHmCH 195-196 24 OlIiHl'INSO4-- 55.55 6.27 15.19 CH3 CHa(CH2)2CH2- CH3 119-120 38 Cii'HigNaOl f,gh 57.14 6.48 14.21

Failed to melt at 360 C. a, not recrystallized, insoluble organic solvents; b, acetonitrile; c, butanone; d, dimethylformamidc; e, acetic acid; f, methyl alcohol; g, benzene;

11, heptane.

Example 8 3O 3. 1,3,8 trimethylpyrido[2,3 d]pyrimidine 2,4,5,7- [1H,3H,6H,8H]tetraone. 1,3,8 trlmetlzylpyrzdo[2,3-d] pyrzmldme 2,4,5,7- 4 1,3,6 trimethylpyrido[2,3 dmwimidim 2, 4,5,1 [1H,3H,6H,8H]tetra0ne sodium salt.-A sample of the [1H3H,6H8H]tetraone product of Example 4 is dissolved in one chemical equiva- 5 1 3 dimethyl 6 (n butyl)pyrid0[ ]PY lent of 5% aqueous sodium hydroxide and the resulting dine 2,457 [1H3H,6H,8H]tetraone solution is concentrated to dryness. The residue remain- 1,3,8 trimethyl 6 (nbmynpyrido[2,3 d]pyrimi ing 15 the sodium salt 0f the starting tetraone. i 2 4 5 7 1 3 The sodium, potassium, and lithium salts of the prod- 7, Pyrido[2,3- ]Py d 2,4,5 [1H,3H 6H ucts of Examples 1 through 7 are prepared and recovtetraone ered in the same fashion. They are useful as interme- 8. A com ound selected from the rou consistin of dlates in substitution reactions employing alkyl and ar- 40 p g p g alkyl esters of strong acids such as alkyl halides and OH sulfates, and alkyland arylisocyanates. G

This application is a continuation-in-part of my co- R pending application, Serial No. 214,187, filed August 2, L l I 1962, and now abandoned. "l5 0: N

While several particular embodiments of this invention a l I are shown above, it will be understood, of course, that a R R the invention is not to be limited thereto Since many and the alkah metal salts thereof, wherein R is selected modifications may be made, and it is contemplated, therefrom the group conslstlng of hydrogen and lower alkyl fore, by the appended claims, to cover any such modifiand and R8 are Selected from the group Consisting cations as fall within the true spirit and scope of this of hydrogen and methyl; invention. 7 9. S-hydroxy 1,3 d1methylpyr1do[2,3 d]pyr1mtdine- What is claimed is:

10. 5 hydroxy 1,3,8 trimethylpyrido[2,3-d]pyrimidine-2,4,7-[1H,3H,8H]trione.

11. S-hydroxy 1,3,6 trimethylpyrido[2,3-d]pyrimidine-2,4,7-[1H,3H,8H]trione.

1. A compound selected from the group consisting of H 12. S-hydroxy 1,3 dimethyl 6 (n-butyl) pyrido Rs [2,3-d]pyrimidine-2,4,7-[1H,3H,8H]trione.

L 13. S-hydroxy 1,3,8 trimethyl 6 (n-butyl)pyrido N [2,3-d]pyrimidine-2,4,7-[1H,3H,8H]trione.

R5 R No references cited.

I UNITED, ST s PATIENT OFFICE GQBBECTION Patent No 3,139,432 June 30 1964 I 3 Homer SCarborough ears in the above numbered pat It is hereby certified, that error app s Patent should read as ent requiring correction andtha'b the said Letter corrected below;

01" read pyrido LlH 3H 6I-1 8H] ovember' 1964.

Column 1, line 38 for "pyrid line 39, for ""[1H,3H,8H] read 3 Signed and sealed t h'is 17th day of N (SEAL) Attest:

EDWARD J BRENNER ERNEST W. SWIDER' Attesting Officer Commissioner of Patents 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF
 8. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF 